Receivers with LFE 80Hz-Crossover, are Front Spkr sets missing their acoustic-mark

Discussion in 'Archived Threads 2001-2004' started by Paul A. Robinso, Dec 8, 2001.

  1. Paul A. Robinso

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    As we(HT-audio enthusiast)sit in our hometheater
    "sweet-spot" what are we not hearing.....
    Most receivers offer LFE-Crossover at 80 or 100Hz
    While for an example your front(Left/Right/Center) set of speakers are designed with a LFE-crossover at 150Hz.
    For lack of a more technical term, this dead sonic space
    between 80Hz and 150Hz is unused (by the speaker and my ear)and this scenerio could just as well apply to the surround speaker's LFE-crossover.
    Am I being to pickey or what your opinion. [​IMG] [​IMG]
    Oh, is their a technical/audio term for this scenerio.
     
  2. Jack Gilvey

    Jack Gilvey Producer

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    There are some speakers sets that applies to, I would consider them lacking. You certainly want speakers that can give good response down to their intended crossover.

    Are you referring to a specific set?
     
  3. BruceD

    BruceD Screenwriter

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    If I were picking speakers (especially mains) for an 80Hz crossover, I would want them to have a -3dB response point down to 40Hz.

    This means reasonable response one octave lower than the crossover. This typically allows the smoothest blend between sub and main speakers.

    Now, all of this also depends on what slope (shallow or steep) the HT processors xover uses as well as the natural low frequency rolloff (slope) of the main speakers. For example, ported speakers will have a different slope than sealed speakers.

    It turns out to be a pretty complicated exercise to get right, but it helps to understand all the variables.

    BruceD
     
  4. Chris PC

    Chris PC Producer

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    I agree that receiver crossovers should go to at least 60 hz, but most are only 80 or 100hz. My front speakers go to 32hz -3 dB, so i could easily get away with 60 hz crossover. My center goes -3 dB to 40 hz, so perhaps my center would be fine at 80 hz.
     
  5. Jimmy P

    Jimmy P Stunt Coordinator

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    Yes,dont buy speakers with a lower limit of 150Hz and a receiver with a 80Hz sub crossover.

    I know what you are saying,and people should pay attention

    to the various hardware combinations they are putting together to avoid problems like you have described,and then

    wonder why their system sounds like crap.
     
  6. Jeremy Anderson

    Jeremy Anderson Screenwriter

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  7. Jack Gilvey

    Jack Gilvey Producer

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  8. Pete Mazz

    Pete Mazz Supporting Actor

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    If the speakers roll off near 80 Hz, they should be ideal for HT using a standard 12 dB 80 Hz HP filter. The sub gets rolled off at 24 Db, so the natural roll off of the speaker combined with the 12 dB roll off of the xover should balance out thru the xover region nicely.

    Pete
     
  9. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    For the sake of argument, you have a THX-spec 80hz crossover with 12dB/octave high pass, and each speaker naturally rolls off at about 12dB/octave past its -3db point (I understand that this is dependant on the speaker, but this is just for the sake of argument). Here are the two scenarios:

    1) A speaker whose -3db point is at 40Hz.

    80Hz = neutral

    40Hz = -15dB

    2) A speaker whose -3dB point is at 80Hz.

    80Hz = -3dB

    40Hz = -27dB

    While I understand that this is an oversimplification, this is just an example. I don't want to go pissing off fans of the JBL's or anything, but they just won't transition as well as a speaker with a slightly better rating. I'll give you this though -- they're great for a beginner package.

    I think I've caused enough arguments for today... so I'm going to bow out for the night.
     
  10. Jack Gilvey

    Jack Gilvey Producer

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    I don't see why anyone would get pissed off. [​IMG] I'm just giving my experience as an owner/user, specs aside. And if being -3db at the crossover is the worst deviation in response someone has, then they have astounding in-room performance (a rather unlikely situation).
    Yes, they are a great "beginner package". Or, for someone like me, who needs something 'til he builds his own. I'll take it over a few of the more costly sets I've heard, though.
     
  11. Pete Mazz

    Pete Mazz Supporting Actor

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  12. BruceD

    BruceD Screenwriter

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    Speaker building specs say a -12db rolloff only occurs with acoustic suspension (sealed) speakers.

    This means most of the speakers we are discussing here are ported and don't have a natural -12dB rolloff. They don't really match up well with the receivers -12dB high pass, instead they cause problems in the crossover region (not a smooth integration between sub and mains).

    I own AR-3a (Acoustic suspension) speakers (don't use them now), Dynaudio Contours (with passive radiators) I do use them in my HT/2-channel system, and demoed a small variety of bass reflex (ported speakers) including B&W with my system.

    The -3dB point and low end rolloff is different on all of them. A symmetrical -24dB high and low pass (Linkwitz-Riley) crossover worked better on all of these speakers than anything provided by a Yamaha receiver or Technics pre-pro.

    That's what I use now with my Dynaudios, a Marchand electronic crossover, crossed over at 60Hz with a Parasound 5 channel amp.

    BruceD
     
  13. John Morris

    John Morris Guest

     
  14. Bryan Acevedo

    Bryan Acevedo Second Unit

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    Jeremy, I think there is one flaw in your argument.

     
  15. Howard_S

    Howard_S Supporting Actor

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    Is 80hz the ideal crossover or something? Is generally higher the better or lower the better assuming you have the most capable speakers etc.
     
  16. Bryan Acevedo

    Bryan Acevedo Second Unit

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    80 Hz has basically been tested as being the optimal setting for not being localizeable. Most people agree that anything lower than this is not directional. However, there are people that say they can tell what direction lower frequencies are coming from.

    This goes back way before the Home Theater days. I remember about 10 years ago, a guy I worked with was a speaker designer, and he told me the best crossover point for a sub was 80 Hz. We were talking about car audio subs, so this is not just something the Home Theater folks came up with.

    Bryan
     
  17. Bryan Acevedo

    Bryan Acevedo Second Unit

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    No one else has anything to add/rebut/say about my post?

    Bryan
     
  18. Paul A. Robinso

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    [​IMG] [​IMG] [​IMG] I agree with most of you and can we all agree that this very topic all Receiver's Bass Management (Wheather THX/DTS requirements) crossover for the Front and Surround speakers should be a marriage/key
    with the speaker's "Low Frequency Response".
    Guys this is what I meant..... [​IMG]
    Jeremy, LFE covers(up to 200Hz)100th of 20,000Khz.
    Ohh, Jeremy thanks, setting my Sub at a higher than 80hz
    crossover, to 120Hz gave me abrouder/deeper bass.
    A 1000.00$ vs a 2000.00$ or greater$, speaker set.
    The mix or overlay of your Front or Surround
    Speaker's Low Frequency Speaker's Limit with what most mid-level receivers/amps (be it 80hz/100hz/120hz) Small/Large crossover is where the the Hometheater sound we
    want to achieve begin and ends.........
    Also I agreed, it's only reasonable to think
    a speaker's Frequency limit varies -/+2db to -/+3db
    for a smoother "Surround Sound", through in Timber matching, Delay, A/V-Sync etc: and well you know....
    Now if I can interest someone in buying a set of 2-year
    old set of Polk-RM5400-series (Hey I didn't know then
    what I know now) Yes the Center down to 125Hz
    the Fronts down to 150hz and
    some good news is the 4-Surrounds down to 70Hz
    and the Sub....down to 30hz to 200hz
    My System Onkyo receiver, TXDS898, it's great.
    Toshiba HD-Monitor, 40H81. Awaiting....
    Onkyo Prog/DVD-A/THX-Ultra DVD-Player DV-S757.
     
  19. Phil Iturralde

    Phil Iturralde Screenwriter

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    Jack Gilvey, myself and other JBL NSP1's users have discovered what Brent Butterworth meant when he documented in his ETown JBL N24 speaker review (part of the JBL NSP1 package)
    Quote:



    . . . -- unlike the SuperZero XU or the ProMonitor 80, this speaker is very easy to match up with practically any subwoofer.




    Jack uses the Sony sub, . . . I use the Audio Source sub, but in both cases, the blending between our 'subs' and NSP1 is excellent. (I MAX'd out the AudioSource Crossover and let my Yamaha 90Hz X-Over do it's job!)

    When Tom Nousaine performed his standard speaker bench-marks on the JBL NSP1 (Sound & Vision, Jan. 2001 issue), the frequency chart reveals why Brent Butterworth wrote what he wrote!

    [​IMG]
    Frequency Response
    N-24 front left/right... 89 Hz to 18.9 kHz ±2.7 dB
    The left/right front speakers were averaged over a ±30° window, with double weight given to the most common listening angle, 30°.

    N-Center................ 89 Hz to 20 kHz ±5.5 dB
    The center speaker's response was averaged over ±45°, with double weight directly on-axis,

    N-24 surround........... 89 Hz to 18.4 kHz ±3.2 dB
    Sound delivered to the listener's ears from surround speakers will be reflected from room surfaces, so their response was averaged over a ±60° window with double weight given to the widest off-axis angles.

    Tom Nousaine noted in the LAB Report: "JBL's N24 left / right satellite had smooth, uniform response over the entire ±60° window."

    The above chart also reveals why these following reviewers wrote about the NSP1's, . . .

    Amazon.com Editorial Review by Wayne Garcia NSP1 Speaker Package

    (partial quotes) As for the NSP1 system's sound, starting with music only, the first thing you'll notice is that it produces surprisingly full audio. Jazz CDs sound rich and clear, . . . Trumpets and saxophones come through with terrific, brassy texture and bite, . . . Vocals are uniformly good--articulate, focused, and well balanced. With orchestral music, the N24s throw a relatively wide soundstage, with more than a hint of depth (that is, of the sonic space extending beyond the speakers).

    With DVD-videos, vocal clarity is enhanced by the N-Center, which does a great job of routing the dialogue to the screen. Considering its small size, the complete NSP1 system exhibits very good dynamics, and JBL's close attention to driver matching yields a seamless transition from speaker to speaker, creating a wonderfully complete sonic environment. (end of quote)

    ====

    August 3, 2000 Brent Butterworth for etown JBL NSP1 speaker system

    (partial quotes) Look & Feel: This system certainly ranks a notch above most of what's available at this price.

    Performance: I've already made detailed performance comments in my reviews of the N24 and N-Center. All I'll say here is that these speakers work together perfectly as an ensemble. The timbre matching is as good as any I've heard; that is, outside of systems that consist of five identical speakers.

    The N-Center matches the sound of the N24 extremely well, better than Home Theater Direct's Level Three center matches the sound of its Level Three bookshelf. That excellent timbre matching lends coherence to the sound of the entire system, making movies seem more like I was hearing them in a real theater, not a home theater. As such, I highly recommend the NSP1 home cinema package to anyone looking to get into home theater without emptying his or her bank account in the process. (end of quotes)

    Compare the JBL NSP1's Frequency Response with other Sound & Vision equivalent and more expensive speaker frequency charts @ my website, Are Bose Speakers Over Priced vs. Performance??

    Watching the dynamic "Pearl Harbor" / SE DVD @ 6 dB below REF Level confirms all the accolades above and then some!! [​IMG] [​IMG] [​IMG] [​IMG] Next, on the agenda is "Jurassic Park III" & "Rush Hour 2" [​IMG]

    For more JBL NSP1 INFO and reviews w/links, see my website Why you should add JBL N & S Series to your audition list!

    NOTE: If too many people peruse my website, GeoCities will shut it down for an hour or so (being a freebie hosting & all), . . . so, just bookmark it and view it at a later time!

    Just an FYI,
    Phil
     
  20. Holadem

    Holadem Lead Actor

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